Exit Earth

A coming threat will render Earth uninhabitable. Neither deep underground fortresses not giant submarines will survive. Humanity must leave Earth to survive. As the leading spacefaring nations, the U.S., Russia, and China will lead an effort to build giant spacecraft that will serve as arks to safeguard a bit of humanity until the Earth can again support life. Russ Corey is a wildcard in the mix since he has personally developed a huge series of lunar bases.